The pressure on agronomists resulting from the worldwide demand for increased food supplies has led to the pursuit of numerous avenues of research in attempts to produce greater yields from the limited area of suitable agricultural land available for the production of agricultural or forest products usable for food or industry. Much effort has been devoted to treatment of seeds with various sorts of energy, among them radioactive, physical, sonic or ultrasonic, magnetic and laser, and numerous sorts of chemical treatments. Many of these processes are laboratory curiosities, experimental in nature, without concrete relation to the realities of commerce. Among the issue U.S. Patents relating to such subject mater are Nos. 43,292, 2,059,835, 2,101,584, 2,300,727, 2,344,151, 2,932,128 and 3,397,640, and the following foreign patents, British No. 743,350; Belgian No. 511,232, German No. 474,454; Canadian No. 608,485; French Nos. 874,656 and 922,132 and Nederlands Nos. 19,358 and 43,753. Low voltage treatment of seeds is discussed in an article entitled "Low Voltage Irradiation of Seeds" published in Agriculture Engineering, Vol. 38, No. 9, pp. 666-9, September, 1957.
While treatments such as these may improve yield, none of them have presented commercially satisfactory solutions to the problem. One of the reasons is that whatever stimulation these various sorts of treatment bring about, it is short-lived; i.e., if the time lapse between treatment and planting is short, improved yields may be established. However, the realities of processing and distributing seeds for agriculture or forest use do not fit in with such a brief time interval of stimulation so that efforts to improve yields along the lines described have proved a waste of time and money considered in the economic aspects of the problem.
Much effort has been expended by scientists in the development of "high yielding varieties" of various types of plants, of which wheat and maize are typical. The difficulty with these genetic innovations is that they have not been time-tested for disease resistance, an example of which was the epidemic of southern corn blight that destroyed a fifth of the United States crop in 1970. An object of this invention is to boost yields of standard varieties of crops or trees which have developed normal disease resistance over many hundreds, if not thousands, of crop generations. I have found, however, as a side effect in respect of tree seeds, at least, that subjection of seeds to my processes not only increases yield but develops disease-resistant characteristics which will be discussed later herein.
My invention is directed to a method of treatment, the apparatus therefor and the product thereof, which will not only stimulate seed growth but stabilize the stimulating factors, whatever they may be, over a reasonable period of time so that the seeds may be transported over whatever distance may be necessary, stored, if necessary, and still retain the efficacy of the stimulating factors so that, when ultimately planted, the seeds will reproduce in the desired quantity. The only attempts in the art known to me to be concerned with the extension in time of optimum seed growth characteristics are disclosed in an article in Science for Dec. 20, 1974, "Viability of Stored Seeds," pp. 1123-4, where experiments with the use of low voltage energy for this purpose are described.
In brief, I subject seeds to microwave energy in an atmosphere, the temperature of which is controlled in a manner hereinafter to be described, then sequentially and immediately after the treatment with microwave energy, I subject the treated seeds to a vacuum treatment, again in a manner hereinafter to be more particularly described. As the result of this sequence of treatments, seeds so treated have been stored for as much as one year while still retaining the same comparable added growth qualities that they would have had had they been planted immediately after treatment. I have found, however, that no only does the vacuum treatment secure the desired stabilizing effect, but that seeds which have been treated with microwave energy and then stabilized per vacua can produce a greater degree of growth and productivity than seeds which have been stimulated by an equivalen microwave treatment and then planted without stabilization. Thus there appears to be a synergistic interaction between the stimulation and the stabilization which produces seeds with superior growth and productive qualities.
As illustrative of the effect of this synergism, samples of bean seeds were subjected to four different sets of conditions as follows:
Sample 1: Microwave energy, cooling and vacuum; PA1 Sample 2: Microwave energy only; PA1 Sample 3: Microwave energy plus cooling; PA1 Sample 4: Vacuum only.
The treated seeds, plus controls, were then planted and observations taken on germination in 65 hours and height of plant at 121/2 days. Taking the growth of the control grown with Sample 1 as an index of 100, the growth of the plants subjected to the several types of treatments described, and the other controls, is set out in the following Table 1:
TABLE I ______________________________________ Va- Microwave Complete Energy Energy plus cuum Time Treatment Only Cooling Only Sample 1 2 3 4 ______________________________________ Control 100 93.4 100 97.7 10 sec. 126.8 93.4 100 93.3 15 sec. 146.7 106.8 120 90.0 20 sec. 106.8 33.4 53.4 93.3 ______________________________________
Samples 1, 2 and 3 comprising three batches were subjected to 500 milliamps of 2450 megahertz for 10, 15 and 20 seconds, respectively; in Samples 1 and 3 the temperature was held to 70.degree.F.; in Samples 1 and 4, the vaccum was 15 inches of Hg absolute for 5 minutes; Sample 4 represented three different batches plus the control and are arrayed opposite the lines of microwave time for convenience only. The treated seeds and controls were planted in flats 1 foot square and 5 inches deep.
I have indicated in this specification that the product treated in accordance with the procedures herein outlined may be stored for as much as a year or more. However, storage should be in facilities at a controlled temperature. I have found that if the temperature is controlled between 34.degree.F. and 70.degree.F., no decline in germination will occur.
The added yields resulting from seed treatments described in this specification will occur if no more than conventional agricultural practices are applied to treated seeds, in planting, care and harvesting. In other words, special inputs of fertilizer, water, insecticides and the like are unnecessary to produce the increased results in yield or growth following my described seed treatment; cf. Science, Dec. 20, 1974, pp. 1085-1088, 1093-1096.
Numerous types of seeds have been treated, planted and harvested, among them Bragg soybeans, Example 1; Davis soybeans, Example 2; Corn Hybrids, Examples 3 to 5; Atlas Cotton Seeds, Example 6; Georgia Early Runner Peanuts, Example 7; Slash Pine Seeds, Examples 8 and 9, and Loblolly Pine Seeds, Examples 10 and 11. Other types of seeds which have responded satisfactorily to the treatment generally described are canteloupe, oats, radishes, Oregon rye, watermelon, wheat, sunflower and tomato seeds.
It has been found in respect of Examples 7 to 11 that the prescribed treatment for seeds has a side effect on the statistical controls of an unexpected nature. In randomized planting controls are statistically located contiguous to treated seeds in accordance with standard statistical theory to secure what are considered objective results. In the planting of the Georgia Early Runner Peanuts of Example 7, controls were located not only randomly within the planting with treated seeds, but were likewise located in a border around the planting. Of the various treated seeds as shown in Example 7, Sample T-3 showed the largest yield, 5,109.6 in pounds per acre, of any of the various treatments. However, the inside controls produced 3,532.7 pounds per acre; the outside controls produced 1,847.52 pounds per acre. While it is impossible to specify the reasons for this effect, it is thought that during the period of growth, the intertwining of the roots of the treated seedlings with those of the controls transfers to the controls in some fashion or other a portion of the benefits derived from the treatment. Where the controls are remote from the treated seeds as in the outside controls, the difference is substantial, e.g., Sample T-3 is 46.0 percentum more productive than the inside controls; it is 177 percentum more productive than the border controls. Thus it is possible by intermixing treated with untreated seeds to increase substantially the productivity of the untreated seeds if they are planted in the same plot.
The same effect is observable in the statistical data on the plantings of slash and loblolly pine set out hereinafter in Examples 8 to 11, respectively. In each of these plantings, no attempt was made to establish border controls as was the case with the Georgia Early Runner Peanuts of Example 7 so that the controls, randomly intermingled in the plantings, must be compared with data for state common and state improved all of which are provided in the examples hereinafter set out.
It will be understood, of course, by persons experienced in this type of work, that each seed of a different class, genus or variety may require differing treatments. What is efficacious for soybeans, will not necessarily produce an equivalent in tree seeds. Equally, different treatments may be required for differing varieties of soybeans. However, within the parameters hereinafter set out explicity, sufficient information is provided so that an operator presented with a type of seed for which treatment data has not been established can determine a preferred treatment for the particular seed in question.
The economic determinant of the efficacy of such treatment is, of course, the increase in harvested bushels per acre for such plants as soybeans. However, with such plants as slash or loblolly pines, the measure is growth per year. Not only do soybeans treated by my methods produce substantially more bushels per acre, slash and loblolly pine seeds treated by my methods, when planted, result in seedlings which grow much more rapidly.
One of the effects I have discovered as the result of treatment in planting is that to the eye of an observer, a field of soybeans planted with seeds so treated is much greener. Analysis indicates that the chlorophyll contents of the leaves and stems of soybeans so treated is higher than normal. Again, in respect of soybeans, normal production of commercially available beans is two beans to a pod; three beans to a pod is common and four beans are occasionally observed. In fields of beans grown from commercial seed treated by my methods, by count, 12 percentum of the pods were four-bean pods. In making this statement, I am mindful of the circumstance that special bean varieties, e.g., those disclosed in Plant Variety Certificate No. 7400094, shows a higher percentage of beans, but by practicing my process, commercial beans which normally would produce very four-bean pods can be stimulated to produce a substantial percentage of four-bean pods.
Another effect of my method of treatment which is particularly significant in tree seedlings in an increase in the hardiness of the seedling. During the course of an experimental planting which was begun prior to the filing of this application, treated loblolly and slash pine seedlings and control seedlings experienced as a random event an unprecedently heavy sleet and ice storm. The 8,000 treated seedlings went through it without any damage while the control seedlings were badly damaged by the event. Other manifestations of the salutary effects of my treatment with tree seedlings are absence of fusiform cankers, tip moth infestation, damping off and chlorosis and no evidence of dormancy.